In the absence of additional information, I default to portfolio for capital gains and losses, and passive for 1231 gains and losses. When I get a K-1 with additional information, that's generally the breakdown. (And then there are the ridiculous nonsense ones, that say "$10 of your qualified dividends are passive," and to them I roll my eyes and move on because there is no way I'm freeing up passive losses against that.)

FYI, you can print the credit form (3800?) to PDF, attach it to the efile, delete the passive credit entries, efile the return, and re-enter the passive credit entries to proforma to the next year, when you have that diagnostic. I actually just duplicate the file, efile the PDF version, and proforma the "as if on paper" version. No way am I paper filing that mess of a return.